Recently, in order to display an image having different directivity, a method for realizing this function with a hologram or a lens array is used. Especially, an apparatus for displaying a three-dimensional image using a electronic display is proposed.
For example, in order to extract a defect of the hologram, by lighting the hologram with vertical illuminating, an inspection apparatus for obtaining the reflected light (image) by a telecentric optical system is proposed (JP-A No. 2006-112991 . . . patent reference 1).
In order to inspect accuracy of a lenticular sheet using a moire, by overlapping a base pitch image (having high accuracy patterning) with the lenticular sheet, an inspection apparatus for analyzing an observed image is proposed (JP-A No. 2005-140041 . . . patent reference 2). Furthermore, in order to obtain a three-dimensional image, an input apparatus for scanning using a special optical system is proposed (JP-A No. 2007-102201 . . . patent reference 3).
However, in the patent reference 1, all directivity of the hologram is obtained by rotating the hologram. Accordingly, the measurement time and a size of the inspection apparatus become a problem. Furthermore, in case of the three-dimensional image displaying apparatus radiating itself, the illuminating is unnecessary while an image generating means is necessary.
In the patent reference 2, accuracy of each part of a three-dimensional image display apparatus can be relatively obtained. However, with regard to the three-dimensional image display apparatus combined with each part, a three-dimensional positional shift cannot be inspected. Furthermore, in the patent reference 3, an analysis means and a display means for inspection are not actually disclosed.